Electronic devices require power to operate. Many electronic devices operate at radio frequencies and can be adversely affected by electromagnetic interference (“EMI”) that gets into the device through the device's power connection. In addition, some sophisticated modern electronic devices operate at relatively low power levels and that can make them even more susceptible to EMI.
Radiated EMI, which comes from electronic devices, travels by being radiated beyond the physical boundaries of the device and things and connections that are physically connected to the device. Having left the physical boundaries of the device radiated EMI can potentially enter all electronic devices that are within its range.
Conducted EMI, which comes from a specific electronic device, can travel through the device's conductive elements and through the conductive elements of things and connections that are physically connected to the device; and therefore potentially to other electronic devices that have a physical connection with that specific electronic device.
Therefore, EMI originating outside of an electronic device can be a problem for the electronic device if it gets into the electronic device; and EMI originating in an electronic device can be a problem for other electronic devices when it leaves the electronic device.
Placing a filtering component or circuit on an electronic device's circuit board is a known solution to reducing incoming and/or outgoing EMI, however, that requires more components on the circuit board, which is a disadvantage in sophisticated electronic devices that have crowded circuit boards.
Another known solution in the art, to reduce both the EMI getting into the device and the EMI being emitted by the device, is the use of inline filters. The disadvantage to an inline filter is that it is an additional component, and whenever an additional component is added into an electronic system, especially systems operating at relatively low power, it can change the characteristics of the system, increasing the probability that it may sooner or more often begin to operate outside of its specification range. Another disadvantage to an inline filter is that it is an extra component which must be purchased and installed, costing money and time.